The vocal expression of emotion was examined with both an auditory experiment and objective acoustic analyses. In the auditory experiment the stimuli were words or short sentences with six basic emotions expressed by two actors. Forty-five undergraduate and graduate students participated in the experiment. The results showed that the vocal expression of emotion was strongly identified, except in the case of fear, and that the six basic emotions could be plotted in a psychological space with two dimensions calculated from multidimensional scaling. The plot formed a roughly circular surface, with locations very similar to those of the facial expressions. One dimension was considered to represent the element of pleasantness-unpleasantness. The actors' voices were then acoustically analyzed. The results suggested that the mean fundamental frequency (F0), the standard deviation (SD) of F0, and the SD of the energy are the important factors that define the characteristics of the vocal expression of emotions. To determine the most important parameter (s) and explain the two dimensions of the psychological space, canonical correlation analysis was conducted. The analysis indicated that F0 was correlated with the pleasantness-unpleasantness dimension.
